Alarm characterization for analyte monitoring devices and systems

ABSTRACT

Methods and apparatus including determining a rate of occurrence of a glycemic excursion event, determining a frequency of an alarm activation associated with the glycemic excursion event, determining an analyte level associated with the alarm activation, and setting an alarm parameter based on one or more of the determined rate of occurrence of the glycemic excursion event, the frequency of the alarm activation associated with the glycemic excursion event or the determined analyte level are provided.

RELATED APPLICATION

The present application claims priority under 35 U.S.C. §119(e) to U.S. provisional application No. 61/113,211 filed Nov. 10, 2008, entitled “Alarm Characterization for an Adjunctive Continuous Glucose Monitoring Device”, the disclosure of which is incorporated herein by reference for all purposes.

BACKGROUND

The detection of the level of analytes, such as glucose, lactate, oxygen, and the like, in certain individuals is vitally important to their health. For example, the monitoring of glucose is particularly important to individuals with diabetes. Diabetics may need to monitor glucose levels to determine when insulin is needed to reduce glucose levels in their bodies or when additional glucose is needed to raise the level of glucose in their bodies.

SUMMARY

Embodiments of the present disclosure include determining a rate of occurrence of a glycemic excursion event, determining a frequency of an alarm activation associated with the glycemic excursion event, determining an analyte level associated with the alarm activation, and setting an alarm parameter based on one or more of the determined rate of occurrence of the glycemic excursion event, the frequency of the alarm activation associated with the glycemic excursion event or the determined analyte level.

In a further aspect, there is provided an interface component, one or more processors operatively coupled to the interface component, and a memory for storing instructions which, when executed by the one or more processors, causes the one or more processors to determine a rate of occurrence of a glycemic excursion event, determine a frequency of an alarm activation associated with the glycemic excursion event, determine an analyte level associated with the alarm activation, and set an alarm parameter based on one or more of the determined rate of occurrence of the glycemic excursion event, the frequency of the alarm activation associated with the glycemic excursion event or the determined analyte level.

These and other features, objects and advantages of the present disclosure will become apparent to those persons skilled in the art upon reading the details of the present disclosure as more fully described below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a block diagram of an embodiment of a data monitoring and management system according to the present disclosure;

FIG. 2 shows a block diagram of an embodiment of the transmitter unit of the data monitoring and management system of FIG. 1;

FIG. 3 shows a block diagram of an embodiment of the receiver/monitor unit of the data monitoring and management system of FIG. 1;

FIG. 4 shows a schematic diagram of an embodiment of an analyte sensor according to the present disclosure;

FIGS. 5A-5B illustrate a perspective view and a cross sectional view, respectively of another embodiment of an analyte sensor;

FIG. 6 is a flowchart illustrating a routine for establishing or setting an alarm parameter based on glycemic excursion events in accordance with one embodiment of the present disclosure; and

FIG. 7 is a flowchart illustrating a routine for determining a rate of occurrence of a glycemic excursion event in accordance with one embodiment of the present disclosure.

INCORPORATION BY REFERENCE

The following patents, applications and/or publications are incorporated herein by reference for all purposes: U.S. Pat. Nos. 4,545,382; 4,711,245; 5,262,035; 5,262,305; 5,264,104; 5,320,715; 5,509,410; 5,543,326; 5,593,852; 5,601,435; 5,628,890; 5,820,551; 5,822,715; 5,899,855; 5,918,603; 6,071,391; 6,103,033; 6,120,676; 6,121,009; 6,134,461; 6,143,164; 6,144,837; 6,161,095; 6,175,752; 6,270,455; 6,284,478; 6,299,757; 6,338,790; 6,377,894; 6,461,496; 6,503,381; 6,514,460; 6,514,718; 6,540,891; 6,560,471; 6,579,690; 6,591,125; 6,592,745; 6,600,997; 6,605,200; 6,605,201; 6,616,819; 6,618,934; 6,650,471; 6,654,625; 6,676,816; 6,676,819; 6,730,200; 6,736,957; 6,746,582; 6,749,740; 6,764,581; 6,773,671; 6,881,551; 6,893,545; 6,932,892; 6,932,894; 6,942,518; 7,167,818; and 7,299,082; U.S. Published Application Nos. 2004/0186365, now U.S. Pat. No. 7,811,231 2005/0182306; 2007/0056858, now U.S. Pat. No. 8,298,389; 2007/0068807, now U.S. Pat. No. 7,846,311; 2007/0227911, now U.S. Pat. No. 7,887,682; 2007/0233013; 2008/0081977, now U.S. Pat. No. 7,618,369; 2008/0161666; and 2009/0054748, now U.S. Pat. No. 7,885,698; U.S. patent application Ser. Nos. 11/396,135, now U.S. Pat. No. 7,620,438, Ser. Nos. 11/537,984, 12/131,012; 12/242,823, now U.S. Pat. No 8,219,173; and Ser. No. 12/363,712, now U.S. Pat. No. 8,346,335; and U.S. Provisional Application Ser. Nos. 61/149,639; 61/155,889; 61/155,891; 61/155,893; 61/165,499; 61/230,686; 61/227,967 and 61/238,461.

DETAILED DESCRIPTION

Before the present disclosure is described, it is to be understood that this disclosure is not limited to particular embodiments described, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present disclosure will be limited only by the appended claims.

Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is encompassed within the disclosure. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges as also encompassed within the disclosure, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the disclosure.

It must be noted that as used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise.

As will be apparent to those of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the present disclosure.

The figures shown herein are not necessarily drawn to scale, with some components and features being exaggerated for clarity.

Generally, embodiments of the present disclosure relate to methods and devices for detecting at least one analyte such as glucose in body fluid. Embodiments relate to the continuous and/or automatic in vivo monitoring of the level of one or more analytes using a continuous analyte monitoring system that includes an analyte sensor at least a portion of which is to be positioned beneath a skin surface of a user for a period of time and/or the discrete monitoring of one or more analytes using an in vitro blood glucose (“BG”) meter and an analyte test strip. Embodiments include combined or combinable devices, systems and methods and/or transferring data between an in vivo continuous system and a BG meter system.

Accordingly, embodiments include analyte monitoring devices and systems that include an analyte sensor—at least a portion of which is positionable beneath the skin of the user—for the in vivo detection, of an analyte, such as glucose, lactate, and the like, in a body fluid. Embodiments include wholly implantable analyte sensors and analyte sensors in which only a portion of the sensor is positioned under the skin and a portion of the sensor resides above the skin, e.g., for contact to a transmitter, receiver, transceiver, processor, etc. The sensor may be, for example, subcutaneously positionable in a patient for the continuous or periodic monitoring of a level of an analyte in a patient's interstitial fluid. For the purposes of this description, continuous monitoring and periodic monitoring will be used interchangeably, unless noted otherwise. The sensor response may be correlated and/or converted to analyte levels in blood or other fluids. In certain embodiments, an analyte sensor may be positioned in contact with interstitial fluid to detect the level of glucose, which detected glucose may be used to infer the glucose level in the patient's bloodstream. Analyte sensors may be insertable into a vein, artery, or other portion of the body containing fluid. Embodiments of the analyte sensors of the subject disclosure may be configured for monitoring the level of the analyte over a time period which may range from minutes, hours, days, weeks, or longer.

Of interest are analyte sensors, such as glucose sensors, that are capable of in vivo detection of an analyte for about one hour or more, e.g., about a few hours or more, e.g., about a few days of more, e.g., about three days or more, e.g., about five days or more, e.g., about seven days or more, e.g., about several weeks or at least one month. Future analyte levels may be predicted based on information obtained, e.g., the current analyte level at time t₀, the rate of change of the analyte, etc. Predictive alarms may notify the user of a predicted analyte level that may be of concern in advance of the user's analyte level reaching the future level. This provides the user an opportunity to take corrective action.

FIG. 1 shows a data monitoring and management system such as, for example, an analyte (e.g., glucose) monitoring system 100 in accordance with certain embodiments. Embodiments of the subject disclosure are further described primarily with respect to glucose monitoring devices and systems, and methods of glucose detection, for convenience only and such description is in no way intended to limit the scope of the disclosure. It is to be understood that the analyte monitoring system may be configured to monitor a variety of analytes at the same time or at different times.

Analytes that may be monitored include, but are not limited to, acetyl choline, amylase, bilirubin, cholesterol, chorionic gonadotropin, creatine kinase (e.g., CK-MB), creatine, creatinine, DNA, fructosamine, glucose, glutamine, growth hormones, hormones, ketone bodies, lactate, peroxide, prostate-specific antigen, prothrombin, RNA, thyroid stimulating hormone, and troponin. The concentration of drugs, such as, for example, antibiotics (e.g., gentamicin, vancomycin, and the like), digitoxin, digoxin, drugs of abuse, theophylline, and warfarin, may also be monitored. In those embodiments that monitor more than one analyte, the analytes may be monitored at the same or different times.

The analyte monitoring system 100 includes a sensor 101, a data processing unit 102 connectable to the sensor 101, and a primary receiver unit 104 which is configured to communicate with the data processing unit 102 via a communication link 103. In certain embodiments, the primary receiver unit 104 may be further configured to transmit data to a data processing terminal 105 to evaluate or otherwise process or format data received by the primary receiver unit 104. The data processing terminal 105 may be configured to receive data directly from the data processing unit 102 via a communication link which may optionally be configured for bi-directional communication. Further, the data processing unit 102 may include a transmitter or a transceiver to transmit and/or receive data to and/or from the primary receiver unit 104 and/or the data processing terminal 105 and/or optionally the secondary receiver unit 106.

Also shown in FIG. 1 is an optional secondary receiver unit 106 which is operatively coupled to the communication link and configured to receive data transmitted from the data processing unit 102. The secondary receiver unit 106 may be configured to communicate with the primary receiver unit 104, as well as the data processing terminal 105. The secondary receiver unit 106 may be configured for bi-directional wireless communication with each of the primary receiver unit 104 and the data processing terminal 105. As discussed in further detail below, in certain embodiments the secondary receiver unit 106 may be a de-featured receiver as compared to the primary receiver, i.e., the secondary receiver may include a limited or minimal number of functions and features as compared with the primary receiver unit 104. As such, the secondary receiver unit 106 may include a smaller (in one or more, including all, dimensions), compact housing or embodied in a device such as a wrist watch, arm band, etc., for example. Alternatively, the secondary receiver unit 106 may be configured with the same or substantially similar functions and features as the primary receiver unit 104. The secondary receiver unit 106 may include a docking portion to be mated with a docking cradle unit for placement by, e.g., the bedside for night time monitoring, and/or a bi-directional communication device. A docking cradle may recharge a powers supply.

Only one sensor 101, data processing unit 102 and data processing terminal 105 are shown in the embodiment of the analyte monitoring system 100 illustrated in FIG. 1. However, it will be appreciated by one of ordinary skill in the art that the analyte monitoring system 100 may include more than one sensor 101 and/or more than one data processing unit 102, and/or more than one data processing terminal 105. Multiple sensors may be positioned in a patient for analyte monitoring at the same or different times. In certain embodiments, analyte information obtained by a first positioned sensor may be employed as a comparison to analyte information obtained by a second sensor. This may be useful to confirm or validate analyte information obtained from one or both of the sensors. Such redundancy may be useful if analyte information is contemplated in critical therapy-related decisions. In certain embodiments, a first sensor may be used to calibrate a second sensor.

The analyte monitoring system 100 may be a continuous monitoring system, or semi-continuous, or a discrete monitoring system. In a multi-component environment, each component may be configured to be uniquely identified by one or more of the other components in the system so that communication conflict may be readily resolved between the various components within the analyte monitoring system 100. For example, unique IDs, communication channels, and the like, may be used.

In certain embodiments, the sensor 101 is physically positioned in or on the body of a user whose analyte level is being monitored. The sensor 101 may be configured to at least periodically sample the analyte level of the user and convert the sampled analyte level into a corresponding signal for transmission by the data processing unit 102. The data processing unit 102 is coupleable to the sensor 101 so that both devices are positioned in or on the user's body, with at least a portion of the analyte sensor 101 positioned transcutaneously. The data processing unit may include a fixation element such as adhesive or the like to secure it to the user's body. A mount (not shown) attachable to the user and mateable with the data processing unit 102 may be used. For example, a mount may include an adhesive surface. The data processing unit 102 performs data processing functions, where such functions may include, but are not limited to, filtering and encoding of data signals, each of which corresponds to a sampled analyte level of the user, for transmission to the primary receiver unit 104 via the communication link 103. In one embodiment, the sensor 101 or the data processing unit 102 or a combined sensor/data processing unit may be wholly implantable under the skin layer of the user.

In certain embodiments, the primary receiver unit 104 may include an analog interface section including an RF receiver and an antenna that is configured to communicate with the data processing unit 102 via the communication link 103, and a data processing section for processing the received data from the data processing unit 102 such as data decoding, error detection and correction, data clock generation, data bit recovery, etc., or any combination thereof.

In operation, the primary receiver unit 104, in certain embodiments, is configured to synchronize with the data processing unit 102 to uniquely identify the data processing unit 102, based on, for example, an identification information of the data processing unit 102, and thereafter, to periodically receive signals transmitted from the data processing unit 102 associated with the monitored analyte levels detected by the sensor 101.

Referring again to FIG. 1, the data processing terminal 105 may include a personal computer, a portable computer such as a laptop or a handheld device (e.g., personal digital assistants (PDAs), telephone such as a cellular phone (e.g., a multimedia and Internet-enabled mobile phone such as an iPhone or similar phone), mp3 player, pager, and the like), drug delivery device, each of which may be configured for data communication with the receiver via a wired or a wireless connection. Additionally, the data processing terminal 105 may further be connected to a data network (not shown) for storing, retrieving, updating, and/or analyzing data corresponding to the detected analyte level of the user.

The data processing terminal 105 may include an infusion device such as an insulin infusion pump or the like, which may be configured to administer insulin to patients, and which may be configured to communicate with the primary receiver unit 104 for receiving, among others, the measured analyte level. Alternatively, the primary receiver unit 104 may be configured to integrate an infusion device therein so that the primary receiver unit 104 is configured to administer insulin (or other appropriate drug) therapy to patients, for example, for administering and modifying basal profiles, as well as for determining appropriate boluses for administration based on, among others, the detected analyte levels received from the data processing unit 102. An infusion device may be an external device or an internal device (wholly implantable in a user).

In certain embodiments, the data processing terminal 105, which may include an insulin pump, may be configured to receive the analyte signals from the data processing unit 102, and thus, incorporate the functions of the primary receiver unit 104 including data processing for managing the patient's insulin therapy and analyte monitoring. In certain embodiments, the communication link 103, as well as one or more of the other communication interfaces shown in FIG. 1, may use one or more of: an RF communication protocol, an infrared communication protocol, a Bluetooth® enabled communication protocol, an 802.11x wireless communication protocol, or an equivalent wireless communication protocol which would allow secure, wireless communication of several units (for example, per HIPAA requirements), while avoiding potential data collision and interference.

FIG. 2 shows a block diagram of an embodiment of a data processing unit of the data monitoring and detection system shown in FIG. 1. User input and/or interface components may be included or a data processing unit may be free of user input and/or interface components. In certain embodiments, one or more application-specific integrated circuits (ASIC) may be used to implement one or more functions or routines associated with the operations of the data processing unit (and/or receiver unit) using for example one or more state machines and buffers.

As can be seen in the embodiment of FIG. 2, the sensor 101 (FIG. 1) includes four contacts, three of which are electrodes—working electrode (W) 210, reference electrode (R) 212, and counter electrode (C) 213, each operatively coupled to the analog interface 201 of the data processing unit 102. This embodiment also shows optional guard contact (G) 211. Fewer or greater electrodes may be employed. For example, the counter and reference electrode functions may be served by a single counter/reference electrode, there may be more than one working electrode and/or reference electrode and/or counter electrode, etc.

FIG. 3 is a block diagram of an embodiment of a receiver/monitor unit such as the primary receiver unit 104 of the data monitoring and management system shown in FIG. 1. The primary receiver unit 104 includes one or more of: a blood glucose test strip interface 301, an RF receiver 302, an input 303, a temperature detection section 304, and a clock 305, each of which is operatively coupled to a processing and storage section 307. The primary receiver unit 104 also includes a power supply 306 operatively coupled to a power conversion and monitoring section 308. Further, the power conversion and monitoring section 308 is also coupled to the receiver processor 307. Moreover, also shown are a receiver serial communication section 309, and an output 310, each operatively coupled to the processing and storage unit 307. The receiver may include user input and/or interface components or may be free of user input and/or interface components.

In certain embodiments, the test strip interface 301 includes a glucose level testing portion to receive a blood (or other body fluid sample) glucose test or information related thereto. For example, the interface may include a test strip port to receive a glucose test strip. The device may determine the glucose level of the test strip, and optionally display (or otherwise notice) the glucose level on the output 310 of the primary receiver unit 104. Any suitable test strip may be employed, e.g., test strips that only require a very small amount (e.g., one microliter or less, e.g., 0.5 microliter or less, e.g., 0.1 microliter or less), of applied sample to the strip in order to obtain accurate glucose information, e.g. Freestyle® blood glucose test strips from Abbott Diabetes Care Inc. Glucose information obtained by the in vitro glucose testing device may be used for a variety of purposes, computations, etc. For example, the information may be used to calibrate sensor 101, confirm results of the sensor 101 to increase the confidence thereof (e.g., in instances in which information obtained by sensor 101 is employed in therapy related decisions), etc.

In further embodiments, the data processing unit 102 and/or the primary receiver unit 104 and/or the secondary receiver unit 106, and/or the data processing terminal/infusion section 105 may be configured to receive the blood glucose value wirelessly over a communication link from, for example, a blood glucose meter. In further embodiments, a user manipulating or using the analyte monitoring system 100 (FIG. 1) may manually input the blood glucose value using, for example, a user interface (for example, a keyboard, keypad, voice commands, and the like) incorporated in the one or more of the data processing unit 102, the primary receiver unit 104, secondary receiver unit 106, or the data processing terminal/infusion section 105.

Additional detailed descriptions are provided in U.S. Pat. Nos. 5,262,035; 5,264,104; 5,262,305; 5,320,715; 5,593,852; 6,175,752; 6,650,471; 6,746,582, and in application Ser. No. 10/745,878 filed Dec. 26, 2003, now U.S. Pat. No. 7,811,231, entitled “Continuous Glucose Monitoring System and Methods of Use”, each of which is incorporated herein by reference.

FIG. 4 schematically shows an embodiment of an analyte sensor in accordance with the present disclosure. This sensor embodiment includes electrodes 401, 402 and 403 on a base 404. Electrodes (and/or other features) may be applied or otherwise processed using any suitable technology, e.g., chemical vapor deposition (CVD), physical vapor deposition, sputtering, reactive sputtering, printing, coating, ablating (e.g., laser ablation), painting, dip coating, etching, and the like. Materials include, but are not limited to, aluminum, carbon (such as graphite), cobalt, copper, gallium, gold, indium, iridium, iron, lead, magnesium, mercury (as an amalgam), nickel, niobium, osmium, palladium, platinum, rhenium, rhodium, selenium, silicon (e.g., doped polycrystalline silicon), silver, tantalum, tin, titanium, tungsten, uranium, vanadium, zinc, zirconium, mixtures thereof, and alloys, oxides, or metallic compounds of these elements.

The sensor may be wholly implantable in a user or may be configured so that only a portion is positioned within (internal) a user and another portion outside (external) a user. For example, the sensor 400 may include a portion positionable above a surface of the skin 410, and a portion positioned below the skin. In such embodiments, the external portion may include contacts (connected to respective electrodes of the second portion by traces) to connect to another device also external to the user such as a transmitter unit. While the embodiment of FIG. 4 shows three electrodes side-by-side on the same surface of base 404, other configurations are contemplated, e.g., fewer or greater electrodes, some or all electrodes on different surfaces of the base or present on another base, some or all electrodes stacked together, electrodes of differing materials and dimensions, etc.

FIG. 5A shows a perspective view of an embodiment of an electrochemical analyte sensor 500 having a first portion (which in this embodiment may be characterized as a major portion) positionable above a surface of the skin 510, and a second portion (which in this embodiment may be characterized as a minor portion) that includes an insertion tip 530 positionable below the skin, e.g., penetrating through the skin and into, e.g., the subcutaneous space 520, in contact with the user's biofluid such as interstitial fluid. Contact portions of a working electrode 501, a reference electrode 502, and a counter electrode 503 are positioned on the portion of the sensor 500 situated above the skin surface 510. Working electrode 501, a reference electrode 502, and a counter electrode 503 are shown at the second section and particularly at the insertion tip 530. Traces may be provided from the electrode at the tip to the contact, as shown in FIG. 5A. It is to be understood that greater or fewer electrodes may be provided on a sensor. For example, a sensor may include more than one working electrode and/or the counter and reference electrodes may be a single counter/reference electrode, etc.

FIG. 5B shows a cross sectional view of a portion of the sensor 500 of FIG. 5A. The electrodes 510, 502 and 503, of the sensor 500 as well as the substrate and the dielectric layers are provided in a layered configuration or construction. For example, as shown in FIG. 5B, in one aspect, the sensor 500 (such as the sensor 101 FIG. 1), includes a substrate layer 504, and a first conducting layer 501, such as carbon, gold, etc., disposed on at least a portion of the substrate layer 504, and which may provide the working electrode. Also shown disposed on at least a portion of the first conducting layer 501 is a sensing layer 508.

A first insulation layer such as a first dielectric layer 505 is disposed or layered on at least a portion of the first conducting layer 501, and further, a second conducting layer 509 may be disposed or stacked on top of at least a portion of the first insulation layer (or dielectric layer) 505. As shown in FIG. 5B, the second conducting layer 509 may provide the reference electrode 502, and in one aspect, may include a layer of silver/silver chloride (Ag/AgCl), gold, etc.

A second insulation layer 506 such as a dielectric layer in one embodiment may be disposed or layered on at least a portion of the second conducting layer 509. Further, a third conducting layer 503 may provide the counter electrode 503. It may be disposed on at least a portion of the second insulation layer 506. Finally, a third insulation layer may be disposed or layered on at least a portion of the third conducting layer 503. In this manner, the sensor 500 may be layered such that at least a portion of each of the conducting layers is separated by a respective insulation layer (for example, a dielectric layer). The embodiment of FIGS. 5A and 5B show the layers having different lengths. Some or all of the layers may have the same or different lengths and/or widths.

In certain embodiments, some or all of the electrodes 501, 502, 503 may be provided on the same side of the substrate 504 in the layered construction as described above, or alternatively, may be provided in a co-planar manner such that two or more electrodes may be positioned on the same plane (e.g., side-by side (e.g., parallel) or angled relative to each other) on the substrate 504. For example, co-planar electrodes may include a suitable spacing there between and/or include dielectric material or insulation material disposed between the conducting layers/electrodes. Furthermore, in certain embodiments one or more of the electrodes 501, 502, 503 may be disposed on opposing sides of the substrate 504. In such embodiments, contact pads may be on the same or different sides of the substrate. For example, an electrode may be on a first side and its respective contact may be on a second side, e.g., a trace connecting the electrode and the contact may traverse through the substrate.

As noted above, analyte sensors may include an analyte-responsive enzyme to provide a sensing component or sensing layer. Some analytes, such as oxygen, can be directly electrooxidized or electroreduced on a sensor, and more specifically at least on a working electrode of a sensor. Other analytes, such as glucose and lactate, require the presence of at least one electron transfer agent and/or at least one catalyst to facilitate the electrooxidation or electroreduction of the analyte. Catalysts may also be used for those analytes, such as oxygen, that can be directly electrooxidized or electroreduced on the working electrode. For these analytes, each working electrode includes a sensing layer (see for example sensing layer 408 of FIG. 5B) proximate to or on a surface of a working electrode. In many embodiments, a sensing layer is formed near or on only a small portion of at least a working electrode.

The sensing layer includes one or more components designed to facilitate the electrochemical oxidation or reduction of the analyte. The sensing layer may include, for example, a catalyst to catalyze a reaction of the analyte and produce a response at the working electrode, an electron transfer agent to transfer electrons between the analyte and the working electrode (or other component), or both.

A variety of different sensing layer configurations may be used. In certain embodiments, the sensing layer is deposited on the conductive material of a working electrode. The sensing layer may extend beyond the conductive material of the working electrode. In some cases, the sensing layer may also extend over other electrodes, e.g., over the counter electrode and/or reference electrode (or counter/reference is provided).

A sensing layer that is in direct contact with the working electrode may contain an electron transfer agent to transfer electrons directly or indirectly between the analyte and the working electrode, and/or a catalyst to facilitate a reaction of the analyte. For example, a glucose, lactate, or oxygen electrode may be formed having a sensing layer which contains a catalyst, such as glucose oxidase, lactate oxidase, or laccase, respectively, and an electron transfer agent that facilitates the electrooxidation of the glucose, lactate, or oxygen, respectively.

In other embodiments the sensing layer is not deposited directly on the working electrode. Instead, the sensing layer 64 may be spaced apart from the working electrode, and separated from the working electrode, e.g., by a separation layer. A separation layer may include one or more membranes or films or a physical distance. In addition to separating the working electrode from the sensing layer the separation layer may also act as a mass transport limiting layer and/or an interferent eliminating layer and/or a biocompatible layer.

In certain embodiments which include more than one working electrode, one or more of the working electrodes may not have a corresponding sensing layer, or may have a sensing layer which does not contain one or more components (e.g., an electron transfer agent and/or catalyst) needed to electrolyze the analyte. Thus, the signal at this working electrode may correspond to background signal which may be removed from the analyte signal obtained from one or more other working electrodes that are associated with fully-functional sensing layers by, for example, subtracting the signal.

In certain embodiments, the sensing layer includes one or more electron transfer agents. Electron transfer agents that may be employed are electroreducible and electrooxidizable ions or molecules having redox potentials that are a few hundred millivolts above or below the redox potential of the standard calomel electrode (SCE). The electron transfer agent may be organic, organometallic, or inorganic. Examples of organic redox species are quinones and species that in their oxidized state have quinoid structures, such as Nile blue and indophenol. Examples of organometallic redox species are metallocenes such as ferrocene. Examples of inorganic redox species are hexacyanoferrate (III), ruthenium hexamine etc.

In certain embodiments, electron transfer agents have structures or charges which prevent or substantially reduce the diffusional loss of the electron transfer agent during the period of time that the sample is being analyzed. For example, electron transfer agents include, but are not limited to, a redox species, e.g., bound to a polymer which can in turn be disposed on or near the working electrode. The bond between the redox species and the polymer may be covalent, coordinative, or ionic. Although any organic, organometallic or inorganic redox species may be bound to a polymer and used as an electron transfer agent, in certain embodiments the redox species is a transition metal compound or complex, e.g., osmium, ruthenium, iron, and cobalt compounds or complexes. It will be recognized that many redox species described for use with a polymeric component may also be used, without a polymeric component.

One type of polymeric electron transfer agent contains a redox species covalently bound in a polymeric composition. An example of this type of mediator is poly(vinylferrocene). Another type of electron transfer agent contains an ionically-bound redox species. This type of mediator may include a charged polymer coupled to an oppositely charged redox species. Examples of this type of mediator include a negatively charged polymer coupled to a positively charged redox species such as an osmium or ruthenium polypyridyl cation. Another example of an ionically-bound mediator is a positively charged polymer such as quaternized poly(4-vinyl pyridine) or poly(1-vinyl imidazole) coupled to a negatively charged redox species such as ferricyanide or ferrocyanide. In other embodiments, electron transfer agents include a redox species coordinatively bound to a polymer. For example, the mediator may be formed by coordination of an osmium or cobalt 2,2′-bipyridyl complex to poly(1-vinyl imidazole) or poly(4-vinyl pyridine).

Suitable electron transfer agents are osmium transition metal complexes with one or more ligands, each ligand having a nitrogen-containing heterocycle such as 2,2′-bipyridine, 1,10-phenanthroline, 1-methyl, 2-pyridyl biimidazole, or derivatives thereof. The electron transfer agents may also have one or more ligands covalently bound in a polymer, each ligand having at least one nitrogen-containing heterocycle, such as pyridine, imidazole, or derivatives thereof. One example of an electron transfer agent includes (a) a polymer or copolymer having pyridine or imidazole functional groups and (b) osmium cations complexed with two ligands, each ligand containing 2,2′-bipyridine, 1,10-phenanthroline, or derivatives thereof, the two ligands not necessarily being the same. Some derivatives of 2,2′-bipyridine for complexation with the osmium cation include, but are not limited to, 4,4′-dimethyl-2,2′-bipyridine and mono-, di-, and polyalkoxy-2,2′-bipyridines, such as 4,4′-dimethoxy-2,2′-bipyridine. Derivatives of 1,10-phenanthroline for complexation with the osmium cation include, but are not limited to, 4,7-dimethyl-1,10-phenanthroline and mono, di-, and polyalkoxy-1,10-phenanthrolines, such as 4,7-dimethoxy-1,10-phenanthroline. Polymers for complexation with the osmium cation include, but are not limited to, polymers and copolymers of poly(1-vinyl imidazole) (referred to as “PVI”) and poly(4-vinyl pyridine) (referred to as “PVP”). Suitable copolymer substituents of poly(1-vinyl imidazole) include acrylonitrile, acrylamide, and substituted or quaternized N-vinyl imidazole, e.g., electron transfer agents with osmium complexed to a polymer or copolymer of poly(1-vinyl imidazole).

Embodiments may employ electron transfer agents having a redox potential ranging from about −200 mV to about +200 mV versus the standard calomel electrode (SCE). The sensing layer may also include a catalyst which is capable of catalyzing a reaction of the analyte. The catalyst may also, in some embodiments, act as an electron transfer agent. One example of a suitable catalyst is an enzyme which catalyzes a reaction of the analyte. For example, a catalyst, such as a glucose oxidase, glucose dehydrogenase (e.g., pyrroloquinoline quinone (PQQ), dependent glucose dehydrogenase, flavine adenine dinucleotide (FAD), or nicotinamide adenine dinucleotide (NAD) dependent glucose dehydrogenase), may be used when the analyte of interest is glucose. A lactate oxidase or lactate dehydrogenase may be used when the analyte of interest is lactate. Laccase may be used when the analyte of interest is oxygen or when oxygen is generated or consumed in response to a reaction of the analyte.

The sensing layer may also include a catalyst which is capable of catalyzing a reaction of the analyte. The catalyst may also, in some embodiments, act as an electron transfer agent. One example of a suitable catalyst is an enzyme which catalyzes a reaction of the analyte. For example, a catalyst, such as a glucose oxidase, glucose dehydrogenase (e.g., pyrroloquinoline quinone (PQQ), dependent glucose dehydrogenase or oligosaccharide dehydrogenase, flavine adenine dinucleotide (FAD) dependent glucose dehydrogenase, nicotinamide adenine dinucleotide (NAD) dependent glucose dehydrogenase), may be used when the analyte of interest is glucose. A lactate oxidase or lactate dehydrogenase may be used when the analyte of interest is lactate. Laccase may be used when the analyte of interest is oxygen or when oxygen is generated or consumed in response to a reaction of the analyte.

In certain embodiments, a catalyst may be attached to a polymer, cross linking the catalyst with another electron transfer agent (which, as described above, may be polymeric. A second catalyst may also be used in certain embodiments. This second catalyst may be used to catalyze a reaction of a product compound resulting from the catalyzed reaction of the analyte. The second catalyst may operate with an electron transfer agent to electrolyze the product compound to generate a signal at the working electrode. Alternatively, a second catalyst may be provided in an interferent-eliminating layer to catalyze reactions that remove interferents.

Certain embodiments include a Wired Enzyme™ sensing layer (Abbott Diabetes Care) that works at a gentle oxidizing potential, e.g., a potential of about +40 mV. This sensing layer uses an osmium (Os)-based mediator designed for low potential operation and is stably anchored in a polymeric layer. Accordingly, in certain embodiments the sensing element is a redox active component that includes (1) Osmium-based mediator molecules attached by stable (bidente) ligands anchored to a polymeric backbone, and (2) glucose oxidase enzyme molecules. These two constituents are crosslinked together.

A mass transport limiting layer (not shown), e.g., an analyte flux modulating layer, may be included with the sensor to act as a diffusion-limiting barrier to reduce the rate of mass transport of the analyte, for example, glucose or lactate, into the region around the working electrodes. The mass transport limiting layers are useful in limiting the flux of an analyte to a working electrode in an electrochemical sensor so that the sensor is linearly responsive over a large range of analyte concentrations and is easily calibrated. Mass transport limiting layers may include polymers and may be biocompatible. A mass transport limiting layer may provide many functions, e.g., biocompatibility and/or interferent-eliminating, etc.

In certain embodiments, a mass transport limiting layer is a membrane composed of crosslinked polymers containing heterocyclic nitrogen groups, such as polymers of polyvinylpyridine and polyvinylimidazole. Embodiments also include membranes that are made of a polyurethane, or polyether urethane, or chemically related material, or membranes that are made of silicone, and the like.

A membrane may be formed by crosslinking in situ a polymer, modified with a zwitterionic moiety, a non-pyridine copolymer component, and optionally another moiety that is either hydrophilic or hydrophobic, and/or has other desirable properties, in an alcohol-buffer solution. The modified polymer may be made from a precursor polymer containing heterocyclic nitrogen groups. For example, a precursor polymer may be polyvinylpyridine or polyvinylimidazole. Optionally, hydrophilic or hydrophobic modifiers may be used to “fine-tune” the permeability of the resulting membrane to an analyte of interest. Optional hydrophilic modifiers, such as poly(ethylene glycol), hydroxyl or polyhydroxyl modifiers, may be used to enhance the biocompatibility of the polymer or the resulting membrane.

A membrane may be formed in situ by applying an alcohol-buffer solution of a crosslinker and a modified polymer over an enzyme-containing sensing layer and allowing the solution to cure for about one to two days or other appropriate time period. The crosslinker-polymer solution may be applied to the sensing layer by placing a droplet or droplets of the solution on the sensor, by dipping the sensor into the solution, or the like. Generally, the thickness of the membrane is controlled by the concentration of the solution, by the number of droplets of the solution applied, by the number of times the sensor is dipped in the solution, or by any combination of these factors. A membrane applied in this manner may have any combination of the following functions: (1) mass transport limitation, i.e., reduction of the flux of analyte that can reach the sensing layer, (2) biocompatibility enhancement, or (3) interferent reduction.

The electrochemical sensors may employ any suitable measurement technique. For example, may detect current or may employ potentiometry. Technique may include, but are not limited to, amperometry, coulometry, voltammetry. In some embodiments, sensing systems may be optical, colorimetric, and the like.

In certain embodiments, the sensing system detects hydrogen peroxide to infer glucose levels. For example, a hydrogen peroxide-detecting sensor may be constructed in which a sensing layer includes enzyme such as glucose oxides, glucose dehydrogenase, or the like, and is positioned proximate to the working electrode. The sending layer may be covered by a membrane that is selectively permeable to glucose. Once the glucose passes through the membrane, it is oxidized by the enzyme and reduced glucose oxidase can then be oxidized by reacting with molecular oxygen to produce hydrogen peroxide.

Certain embodiments include a hydrogen peroxide-detecting sensor constructed from a sensing layer prepared by crosslinking two components together, for example: (1) a redox compound such as a redox polymer containing pendent Os polypyridyl complexes with oxidation potentials of about +200 mV vs. SCE, and (2) periodate oxidized horseradish peroxidase (HRP). Such a sensor functions in a reductive mode; the working electrode is controlled at a potential negative to that of the Os complex, resulting in mediated reduction of hydrogen peroxide through the HRP catalyst.

In another example, a potentiometric sensor can be constructed as follows. A glucose-sensing layer is constructed by crosslinking together (1) a redox polymer containing pendent Os polypyridyl complexes with oxidation potentials from about −200 mV to +200 mV vs. SCE, and (2) glucose oxidase. This sensor can then be used in a potentiometric mode, by exposing the sensor to a glucose containing solution, under conditions of zero current flow, and allowing the ratio of reduced/oxidized Os to reach an equilibrium value. The reduced/oxidized Os ratio varies in a reproducible way with the glucose concentration, and will cause the electrode's potential to vary in a similar way.

A sensor may also include an active agent such as an anticlotting and/or antiglycolytic agent(s) disposed on at least a portion a sensor that is positioned in a user. An anticlotting agent may reduce or eliminate the clotting of blood or other body fluid around the sensor, particularly after insertion of the sensor. Examples of useful anticlotting agents include heparin and tissue plasminogen activator (TPA), as well as other known anticlotting agents. Embodiments may include an antiglycolytic agent or precursor thereof. Examples of antiglycolytic agents are glyceraldehyde, fluoride ion, and mannose.

Sensors may be configured to require no system calibration or no user calibration. For example, a sensor may be factory calibrated and need not require further calibrating. In certain embodiments, calibration may be required, but may be done without user intervention, i.e., may be automatic. In those embodiments in which calibration by the user is required, the calibration may be according to a predetermined schedule or may be dynamic, i.e., the time for which may be determined by the system on a real-time basis according to various factors, such as, but not limited to, glucose concentration and/or temperature and/or rate of change of glucose, etc.

Calibration may be accomplished using an in vitro test strip (or other reference), e.g., a small sample test strip such as a test strip that requires less than about 1 microliter of sample (for example Freestyle® blood glucose monitoring test strips from Abbott Diabetes Care). For example, test strips that require less than about 1 nanoliter of sample may be used. In certain embodiments, a sensor may be calibrated using only one sample of body fluid per calibration event. For example, a user need only lance a body part one time to obtain sample for a calibration event (e.g., for a test strip), or may lance more than one time within a short period of time if an insufficient volume of sample is firstly obtained. Embodiments include obtaining and using multiple samples of body fluid for a given calibration event, where glucose values of each sample are substantially similar. Data obtained from a given calibration event may be used independently to calibrate or combined with data obtained from previous calibration events, e.g., averaged including weighted averaged, etc., to calibrate. In certain embodiments, a system need only be calibrated once by a user, where recalibration of the system is not required.

Analyte systems may include an optional alarm system that, e.g., based on information from a processor, warns the patient of a potentially detrimental condition of the analyte. For example, if glucose is the analyte, an alarm system may warn a user of conditions such as hypoglycemia and/or hyperglycemia and/or impending hypoglycemia, and/or impending hyperglycemia. An alarm system may be triggered when analyte levels approach, reach or exceed a threshold value. An alarm system may also, or alternatively, be activated when the rate of change, or acceleration of the rate of change, in analyte level increase or decrease, approaches, reaches or exceeds a threshold rate or acceleration. A system may also include system alarms that notify a user of system information such as battery condition, calibration, sensor dislodgment, sensor malfunction, etc. Alarms may be, for example, auditory and/or visual. Other sensory-stimulating alarm systems may be used including alarm systems which heat, cool, vibrate, or produce a mild electrical shock when activated.

Referring back to the figures, FIG. 6 illustrates steps for setting, determining or programming an alarm parameter based on glycemic excursion events in one embodiment of the present disclosure. The alarm parameter may be based on, but not limited to, a determined rate of occurrence of a glycemic excursion event (610) such as hypoglycemia or hyperglycemia, a determined frequency of alarm activation based on the glycemic excursion event (620), and/or a determined glucose level associated with the alarm activation (630).

In one aspect, the rate of occurrence of a glycemic excursion event (610) may be determined by analyzing glycemic related data for a predetermined time period, as illustrated in the flow chart of FIG. 7. Referring to FIG. 7, in one embodiment, the rate of occurrence of a glycemic excursion event is determined by monitoring a glucose level of a patient for a predetermined time period (710). During this predetermined time period, the occurrence or the frequency of the occurrence of the glucose level of the patient crossing or transcending a predetermined threshold is detected (720). The predetermined threshold, in one aspect, may be based on one or more threshold levels or parameters associated with one or more conditions, such as, for example, but not limited to, hypoglycemic condition, hyperglycemic condition, impending hyperglycemic or impending hypoglycemic conditions, a rate of change of the glucose or analyte level exceeding a set or programmed rate, or a rate of acceleration or deceleration of the glucose or analyte level fluctuation. For example, the predetermined threshold for mild hypoglycemia may be associated with a blood glucose level of approximately 70 mg/dL and the threshold for moderate hypoglycemia may be associated with a blood glucose level of approximately 60 mg/dL. Referring back to FIG. 7, the detection of the glucose level transcending or crossing the predetermined threshold may be stored in a memory or a suitable storage device such as random access memory (RAM), electrically programmable random access memory (EPROM), Flash memory and the like, and the stored information may be used to determine the rate of occurrence of the glycemic event during the predetermined time period (730).

Referring back to FIG. 6, the frequency of an alarm activation associated with the glycemic excursion event (620) is determined, as well as the glucose level associated with the alarm activation (630), which, in one aspect, is determined based on analyte sensor data received from a transcutaneous analyte sensor, such as a glucose sensor. Once the rate of occurrence of the glycemic excursion event, and the frequency of alarm activation and associated glucose level are determined, an alarm parameter may be set or programmed (or programmable) based on the determined information (640). In other aspects, information, such as the rate of change of the glucose level associated with the glycemic excursion event or the associated alarm activation or trigger event, may be determined and used to, in part, base or determine the setting/establishing of the alarm parameter. Moreover, once the alarm parameter is set or established, the alarm parameter may be used to program a notification function or routine associated with the analyte monitoring systems.

As described above, in accordance with aspects of the present disclosure, alarm or notification routines or functions may be programmed, programmable or provided to a user or a patient in conjunction with the use of an analyte monitoring system including an analyte monitoring device such as, for example, a continuous glucose sensor that provides real time monitoring of glucose levels of the patient or the user. For example, in one aspect, the frequency of the occurrence of a notification or alarm associated with a particular condition (such as, for example, a hypoglycemic condition) may be detected. The detected occurrence of such notification may be provided to an analyte monitoring system (or retrieved from the storage device or memory of such monitoring systems) and processed for further characterization, personalization or programming to improve glycemic control resulting in health treatment or therapy management.

In one aspect, programming or configuring an analyte monitoring system or other physiological condition monitoring device or system to provide notification function and/or alarm features may include monitoring and/or evaluating analyte level information obtained from a transcutaneously positioned analyte sensor, detecting conditions associated with the notification or alarm such as, for example, but not limited to, hypoglycemia, or hyperglycemia, obtaining an in vitro blood glucose measurement when the notification or alarm is output or asserted, and/or determining the frequency of such notification or alarms asserted or output to the user or the patient. In certain aspects, the in vitro blood glucose measurement results may be used to confirm the blood glucose level, for example, by comparing the analyte level associated with the asserted or output alarm notification detected and analyzed from the analyte sensor to the in vitro blood glucose measurements. In certain embodiments, the monitored analyte level information from the transcutaneously positioned in vivo analyte sensor may be used solely to determine whether the alarm or notification is triggered and not subsequently comparing the analyte level with the results of a contemporaneous in vitro blood glucose measurement. In a further aspect, the frequency of the alarm or notification assertion (which is related to or triggered by the monitored analyte level transcending or crossing a predetermined threshold level or rate of change of such monitored analyte level) may be used as a parameter or factor in determining, modifying or adjusting the alarm parameters.

In certain aspects, the detection of the alarm condition or the underlying physiological condition associated with the programmed notification includes the detection of such conditions within approximately 30 minutes of the occurrence of such conditions. For example, multiple data points received from the in vivo analyte sensor may be compared to determine (1) onset of such condition, (2) the occurrence of such condition, or (3) termination of such condition. That is, in one aspect, the alarm or notification occurrence frequency may be evaluated to determine or confirm the presence of the underlying alarm condition or the onset of the alarm condition.

Accordingly, in aspects of the present disclosure, depending upon the threshold level setting for the hypoglycemic alarm condition, the percentage of detection and/or the number of alarms/notifications triggered may vary. That is, to adjust or modify an alarm setting for an underlying condition such as the detection of or the onset of a hypoglycemic condition, the frequency of such alarm occurrence over a predetermined time period may be evaluated in conjunction with or in addition to the assessment of the monitored level rate of change information, and the in vitro blood glucose measurement reading when the alarm is asserted, among others.

In the manner described above, in accordance with aspects of the present disclosure, a user, patient or a healthcare provider may customize or adjust the notification functions or alarms programmed or programmable in analyte monitoring devices and systems such as in continuous glucose monitoring systems such that the customized or adjusted notifications or alarms are more effective in notifying, alerting and/or prompting the user or the patient to take timely corrective actions based on such notifications. For example, if a user or a patient has a relatively high tolerance level for glycemic excursions and does not wish to have the notifications or alarms associated with glycemic excursions that are relatively mild (or within a narrower range of variation), based on the frequency of the alarms or notifications that have occurred during the use of the analyte monitoring device (for example, during a five day period, or on a bi-weekly or monthly basis, or with each replacement of the analyte sensor), the user or the patient may adjust or modify the alarm or notification thresholds or parameters based on, among others, the frequency of the previously triggered notifications and/or alarms, the levels of the thresholds or set (or programmed) levels, and the like. In this manner, a more effective programming of the notification or alarm functions/features in conjunction with the monitored analyte levels may be provided to improve glycemic control and health management.

Accordingly, a method in one aspect includes determining a rate of occurrence of a glycemic excursion event, determining a frequency of an alarm activation associated with the glycemic excursion event, determining an analyte level associated with the alarm activation, and setting an alarm parameter based on one or more of the determined rate of occurrence of the glycemic excursion event, the frequency of the alarm activation associated with the glycemic excursion event or the determined analyte level.

The glycemic excursion event may include one of hypoglycemic event or hyperglycemic event.

In one aspect, determining the analyte level associated with the alarm activation may be based, at least in part, on analyte sensor data from a transcutaneous analyte sensor.

The analyte sensor may include a glucose sensor.

Also, determining a rate of occurrence of the glycemic excursion event may include monitoring a glucose level for a predetermined time period, detecting the monitored glucose level transcending a predetermined threshold glucose level, and determining the rate of occurrence based on the detected monitored glucose level transcending the predetermined threshold glucose level within the predetermined time period.

Moreover, in another aspect, the method may include determining a rate of change of the analyte level associated with the glycemic excursion event or the alarm activation, or a combination thereof.

In a further aspect, the method may include programming an alarm function based on the set alarm parameter.

An apparatus in another aspect of the present disclosure includes an interface component such as a display unit, a user interface component including input/output units, and the like, one or more processors operatively coupled to the interface component; and a memory for storing instructions which, when executed by the one or more processors, causes the one or more processors to determine a rate of occurrence of a glycemic excursion event, determine a frequency of an alarm activation associated with the glycemic excursion event, determine an analyte level associated with the alarm activation, and set an alarm parameter based on one or more of the determined rate of occurrence of the glycemic excursion event, the frequency of the alarm activation associated with the glycemic excursion event or the determined analyte level.

Another embodiment may include monitoring an analyte level for a predetermined time period, detecting the monitored analyte level crossing a predetermined threshold glucose level, determining a frequency of the detected monitored analyte level crossing the predetermined threshold analyte level within the predetermined time period, determining an analyte level associated with an alarm threshold condition, and updating an alarm parameter related to the monitored analyte level based on the determined frequency of the detected monitored analyte level crossing the predetermined threshold analyte level within the predetermined time period.

The detected analyte level crossing the predetermined threshold glucose level may be associated with an impending hypoglycemic event or an impending hyperglycemic event.

The analyte level may be a glucose level.

Moreover, an aspect may include determining a rate of change of the analyte level associated with the detected monitored analyte level crossing the predetermined threshold glucose level

Updating the alarm parameter may include modifying an alarm triggering threshold level.

The various processes described above including the processes performed by the processor 204 (FIG. 2) in the software application execution environment in the analyte monitoring system 100 (FIG. 1) as well as any other suitable or similar processing units embodied in the processing and storage unit 307 (FIG. 3) of the primary/secondary receiver unit 104/106, and/or the data processing terminal/infusion section 105, including the processes and routines described hereinabove, may be embodied as computer programs developed using an object oriented language that allows the modeling of complex systems with modular objects to create abstractions that are representative of real world, physical objects and their interrelationships. The software required to carry out the inventive process, which may be stored in a memory or storage unit (or similar storage devices in the one or more components of the system 100 and executed by the processor, may be developed by a person of ordinary skill in the art and may include one or more computer program products.

Various other modifications and alterations in the structure and method of operation of the embodiments of the present disclosure will be apparent to those skilled in the art without departing from the scope and spirit of the present disclosure. Although the present disclosure has been described in connection with certain embodiments, it should be understood that the present disclosure as claimed should not be unduly limited to such embodiments. It is intended that the following claims define the scope of the present disclosure and that structures and methods within the scope of these claims and their equivalents be covered thereby. 

What is claimed is:
 1. A method, comprising: positioning an in vivo analyte sensor in fluid contact with interstitial fluid under a skin surface; monitoring an analyte level in the interstitial fluid with the in vivo analyte sensor; determining, using one or more processors, a rate of occurrence of a glycemic excursion event based on the monitored analyte level; determining, using the one or more processors, a number of alarm activations associated with the glycemic excursion event based on the monitored analyte level; setting, using the one or more processors, a parameter for the alarm activation based on the determined rate of occurrence of the glycemic excursion event and the number of alarm activations associated with the glycemic excursion event, wherein setting the parameter for the alarm activation is programmable; and controlling administration of therapy based on the parameter for the alarm activation.
 2. The method of claim 1, wherein the glycemic excursion event includes one of a hypoglycemic event or a hyperglycemic event.
 3. The method of claim 1, further including determining an analyte level associated with the alarm activation based at least in part on analyte sensor data from the in vivo analyte sensor.
 4. The method of claim 3, including determining a rate of change of the analyte level associated with the glycemic excursion event or the alarm activation, or a combination thereof.
 5. The method of claim 3, wherein the transcutaneous analyte sensor comprises a plurality of electrodes including a working electrode, wherein the working electrode comprises an analyte-responsive enzyme and a mediator, wherein at least one of the analyte-responsive enzyme and the mediator is chemically bonded to a polymer disposed on the working electrode, and wherein at least one of the analyte-responsive enzyme and the mediator is crosslinked with the polymer.
 6. The method of claim 1, wherein determining the rate of occurrence of the glycemic excursion event includes: monitoring a glucose level for a predetermined time period; detecting the monitored glucose level transcending a predetermined threshold glucose level; and determining the rate of occurrence based on the detected monitored glucose level transcending the predetermined threshold glucose level within the predetermined time period.
 7. The method of claim 1, including programming an alarm function based on the parameter for the alarm activation.
 8. The method of claim 1, wherein the number of alarm activations is a number of alarm occurrences over a predetermined time period, and wherein setting the parameter for the alarm activation includes modifying a threshold level of the alarm activation based on determining the number of alarm activations.
 9. The method of claim 1, wherein modifying the parameter for the alarm activation is programmable to reduce the rate of occurrence of the glycemic excursion event.
 10. The method of claim 1, including generating a notification function associated with an analyte monitoring system when the programmable parameter for the alarm activation is set.
 11. The method of claim 10, wherein the notification function includes outputting information corresponding to the set parameter for the alarm activation.
 12. An apparatus, comprising: an interface component; one or more processors operatively coupled to the interface component; and a memory storing instructions which, when executed by the one or more processors, causes the one or more processors to determine a rate of occurrence of a glycemic excursion event based on monitored analyte level from an in vivo analyte sensor in fluid contact with interstitial fluid under a skin surface, determine a number of alarm activations associated with the glycemic excursion event based on the monitored analyte level, and set a parameter for the alarm activation based on the determined rate of occurrence of the glycemic excursion event and the frequency of the alarm activation associated with the glycemic excursion event, and control administration of therapy based on the parameter for the alarm activation, wherein setting the parameter for the alarm activation is programmable.
 13. The apparatus of claim 12, wherein the glycemic excursion event includes one of a hypoglycemic event or a hyperglycemic event.
 14. The apparatus of claim 12, wherein the memory storing instructions which, when executed by the one or more processors, causes the one or more processors to determine an analyte level associated with the alarm activation based at least in part on analyte sensor data from the in vivo analyte sensor.
 15. The apparatus of claim 14, wherein the transcutaneous analyte sensor comprises a plurality of electrodes including a working electrode, wherein the working electrode comprises an analyte-responsive enzyme and a mediator, wherein at least one of the analyte-responsive enzyme and the mediator is chemically bonded to a polymer disposed on the working electrode, and wherein at least one of the analyte-responsive enzyme and the mediator is crosslinked with the polymer.
 16. The apparatus of claim 12, wherein the memory storing instructions which, when executed by the one or more processors, causes the one or more processors to monitor a glucose level for a predetermined time period, detect the monitored glucose level transcending a predetermined threshold glucose level, and determine the rate of occurrence based on the detected monitored glucose level transcending the predetermined threshold glucose level within the predetermined time period.
 17. The apparatus of claim 12, wherein the memory storing instructions which, when executed by the one or more processors, causes the one or more processors to determine a rate of change of an analyte level associated with the glycemic excursion event or the alarm activation, or a combination thereof.
 18. The apparatus of claim 12, wherein the memory storing instructions which, when executed by the one or more processors, causes the one or more processors to program an alarm function based on the parameter for the alarm activation.
 19. The apparatus of claim 12, wherein the interface component includes an output unit, and further, wherein the parameter for the alarm activation is displayed on the output unit.
 20. The apparatus of claim 12, wherein the number of alarm activations is a number of occurrences of the alarm activation over a predetermined time period, and wherein the memory storing instructions which, when executed by the one or more processors, causes the one or more processors to modify a threshold level of the alarm activation based at least in part on the number of alarm activations over a predetermined time period.
 21. A method, comprising: monitoring an analyte level based on one or more signals generated from a factory calibrated in vivo analyte sensor in fluid contact with interstitial fluid; determining, using one or more processors, a number of alarm activations associated with a glycemic excursion event based on the monitored analyte level; setting, using the one or more processors, a parameter for the alarm activation based on a determined rate of occurrence of the glycemic excursion event and the number of alarm activations associated with the glycemic excursion event; outputting a notification associated with the parameter for the alarm activation; and controlling administration of therapy based on the parameter for the alarm activation; wherein the parameter for the alarm activation is updated after outputting the notification associated with the parameter for the alarm activation.
 22. The method of claim 21, wherein the in vivo analyte sensor is calibrated without an in vitro analyte measurement obtained when the one or more signals are generated from the in vivo analyte sensor. 